While a major purpose of the use of cosmetics is to enhance or emphasize certain facial features, such as the eyes or lips, another important use is diminishing the appearance of facial or other bodily features that are less than perfect. Few consumers are blessed with flawless skin, and concealment of facial flaws is a crucial function of any truly functional makeup. The challenge of the cosmetic formulator is to provide a makeup that will mask the imperfections, and yet let the desirable aspects of the user's skin shine through. In other words, a useful concealer will hide blemishes, and yet overall leave the skin with a natural glowing appearance that is characteristic of bare, unflawed skin.
Attaining this end is not so simple. The characteristic method of concealing skin imperfections has, in the not so distant past, been to apply what is substantially a “mask”, i.e., an opaque physical covering for the blemish that literally hides it from view. This has been routinely done by use of makeups that contain high levels of metal oxides, which are substantially opaque and therefore provide a fairly effective barrier to visibility of the flaw lying beneath. Although effective in concealing, this type of makeup has many drawbacks. First, they tend to be thick and heavy, as a result of the high level of pigment needed to provide physical concealment. More importantly, however, they leave the user's face with a matte, uniform, very unnatural appearance which few consumers will find desirable.
In recent years, the trend has been to develop makeups that, rather than physically masking flaws, attempt to fool the observer's eye into not seeing them. This is done by exploiting the optical properties of certain types of pigments. Various types of interference pigments, for example, reflect light in such a way as to prevent the observer's eye from seeing the blemish that lies beneath the pigment. A number of makeup compositions based on the use of interference pigments, or optical properties of other cosmetic powders, have recently been reported (e.g., U.S. Pat. No. 5,690,916; WO 01/51017) However, there continues to be a need for a makeup that provides a truly effective “concealer” effect, without the substantial use of opacifying pigments, so that a natural, transparent, flawless bare skin look is achieved.